Analyzing campaign expenditures, the media has had as a focus the high

in D, " have x as a focus" is meaningless.
I focus on this topic. correct
I have this topic as a focus. wrong
I have this topic as my focus. correct.

so, we need "their" before "focus". but even if we add "their", the sentence is wordy. because use of verb is more concise than the use of "have+noun" or "there is+noun"

on gmat , we see some phrases such as : have +noun, take +noun, there is +noun. the verb take, have , there is, need a noun to have complete meaning.
all of these phrase are considered wordy and indirect than the use of only verb. see examples folloing

I will learn gmat tomorow
I will take the learning of gmat tomorow
I will join gmat class tomorow
I will have a participation of gmat class tomorow
some alient exists here
there is an alient existing here.
I will act now
Iwill take action noun.

if we see these phrase and a choice using only verb, take the choice using verb because it is concise and direct.